Respective roles of 25 hydroxy-vitamin D, PTH, phosphate and renal function for the 1-alpha-hydroxylase activity in primary hyperparathyroidism.
Forty-three women (mean age 67 years, range 34-84 years) with primary hyperparathyroidism were investigated in an effort to examine the regulation of the 1-alpha-hydroxylase. This enzyme catalyzes the 1-hydroxylation of 25-hydroxy-vitamin D [25(OH)vit D] to 1,25-dihydroxy-vitamin D [1,25(OH)2vit D]. Serum 25(OH)vit D, 1,25(OH)2vit D, PTH, ionized calcium, phosphate and the 24-hour clearance of creatinine were measured. Different linear regression models were calculated with 1,25(OH)2vit D as the dependent variable. 25(OH)vit D was found to be definitely important for the regulation. The role of PTH for the 1,25(OH)2vit D production was discussed. Both renal function and phosphate concentration were found to influence the 1-alpha-hydroxylation.
Frølich
A
A
Department of Clinical Chemistry, Herlev Hospital, University of Copenhagen, Denmark.
Nielsen
B F
BF
Transbøl
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D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000494:pharmacology*; D006900:Hydroxylation; D006961:Hyperparathyroidism / Q000201:enzymology / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000502:physiology*; D010710:Phosphates / Q000097:blood / Q000378:metabolism* / Q000652:urine
D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D010710:Phosphates; D006899:Mixed Function Oxygenases; D002118:Calcium